以两年生山定子(Malus baccata(L.)Borkh)盆栽苗为材料,正常浇水为对照,控水条件下喷施不同浓度(0、25、50、75、100 mg/L)5-氨基乙酰丙酸(ALA),测定各持续干旱胁迫时期(第0、4、8、12天)叶片的抗旱生理指标及光合荧光参数,研究ALA对干旱胁迫下山定子叶绿素荧光和抗逆生理生化特性的影响及其调节机制.结果显示:(1)持续干旱胁迫条件下,外源ALA处理使得山定子叶片渗透调节物质(SS、SP、Pro)含量增加,抗氧化酶(SOD、POD、APX)活性升高,丙二醛(MDA)积累减少.(2)ALA处理增大了干旱胁迫下山定子叶片的气孔开度,促进叶绿素的合成,并对干旱引起的最大光化学效率(Fv/Fm)、实际光量子效率(Y u)、光化学淬灭系数(qP)及光合电子传递速率(ETR)的减小,以及PSⅡ调节性能量耗散的量子产额(YNPQ)、非调节性能量耗散的量子产额(YNO)和非光化学淬灭系数(NPQ/4)的增大有明显的缓解作用.研究认为,外喷ALA能够有效缓解干旱胁迫对山定子生理代谢功能的损伤,但干旱胁迫条件下山定子对不同浓度ALA响应程度不尽相同,其中以75 mg/L的ALA处理效果较为理想.%Two-year-old potted Malus baccata seedlings was used as experiment materials.Normal watering was used as the control CK,different concentrations of ALA (0/25/50/75 mg/L) were sprayed under drought stress.The physiological indexes of drought resistance and photosynthetic fluorescence parameters in leaves at different periods of continuous stress (day 0/4/8/12) were measured.The effects of ALA on chlorophyll fluorescence,physiological and biochemical characteristics of chlorophyll fluorescence and its regulation mechanism under drought stress were studied.The results showed that:(1) exogenous ALA increased the contents of osmolytes (SS,SP,Pro) and promoted the activities of antioxidant enzymes (SOD,POD and APX),while reduced the accumulation of malondialdehyde (MDA) in M.baccata under continuous drought stress conditions;(2) exogenous ALA increased the stomatal opening in leaves of M.baccata,promoted the synthesis of chlorophyll,and significantly alleviated the decrease of the maximum photochemical rate of chlorophyll fluorescence parameters (Fv/Fm),the actual photochemical efficiency (YⅡ),the photochemical quenching coefficient (qP) and the photosynthetic electron transport rate (ETR),as well as the increase of the quantum yield of PSⅡ regulated energy dissipation (YNPQ),quantum yield of non-regulated energy dissipation (YNO) and non-photochemical quenching coefficient (NPQ/4) induced by drought.The results showed that the application of ALA could relieve the damage of the physiological and metabolic function of M.baccata under drought stress.However,there was a difference in response to different concentrations of ALA in M.baccata,of which 75 mg/L ALA had the most significant effect.
展开▼
